This invention relates generally to apparatus and method for terminating a multiconductor cable to an electrical connector and, more particularly, to a compact, manually operated, portable tool for terminating the insulated conductors of a multiconductor cable to the insulation-piercing contacts of a multicontact connector.
Multicontact electrical connectors are commonly used in communications, instrumentation, data processing, avionics, and other fields to interconnect numerous circuits, often in very confined areas. These connectors are used, for example, in high density rack-and-panel, cable-to-panel and cable-to-cable applications because they provide a multiplicity of precisely aligned miniature contacts in a compact connector body designed for straightforward and reliable mating.
One type of multicontact electrical connector widely employed in the telecommunications field is exemplified by Bunker Ramo Corporation's 57 Series connector. This connector features a plurality of miniature contacts precisely aligned in closely spaced vertical channels along the elongated parallel edges of a dielectric insert. Each of the contacts has an exposed insulation-piercing termination portion having one or more notches with opposed edges for cutting through the conductor insulation to produce a solderless electrical connection to a corresponding one of the insulated conductors. Since the telephone industry generally employs a standard jacketed cable having twenty-five color-coded pairs of insulated conductors in five standard color subgroupings, a most popular form of this connector has twenty-five pairs of contacts spaced along the elongated edges of the connector dielectric, the contacts of each pair being on opposite edges of the dielectric. In wiring the connector, the twenty-five pairs of conductors are carefully sorted and terminated to the connector contacts in a standarized deployment according to color.
Typically, the connectors are initially wired in the factory, usually with semiautomatic termination equipment engineered for rapid, heavy-duty usage in continuous assembly line operations. These machines may include, for example, fixed guide combs between which the connector is positioned, the individual conductors being received and held initially in the guide combs in alignment with the corresponding connector-mounted contacts, and a ram mechanism having punches which slide between the combs to laterally insert the conductors into the insulation-piercing termination portions and terminate the conductors in the contacts. AC electrical power is usually required, and hydraulic or pneumatic drives may be used, requiring oil or water reservoirs or compressed air lines. Semiautomatic termination equipment is therefore generally complex, bulky, and expensive.
One particularly successful semiautomatic termination apparatus is described in the present inventor's U.S. Pat. No. 3,967,356. This apparatus supports the multicontact connector in a stationary position, and conductor spacing and dressing combs are fixed alongside the connector to align the conductors with the appropriate contacts prior to termination. A carriage carries insertion heads along the connector support to predetermined positions where conductor insertion operations are performed on groups of conductors. Movement of the carriage and operation of the insertion heads are pneumatically controlled. While the design and operation of this apparatus is well-suited for its intended purpose of rapid and reliable assembly line wiring of multiconductor connectors, it is not physically or economically practical to carry such apparatus into the field to meet occasional wiring needs.
Yet, after installation, field replacement of these multicontact connectors may be required for a number of reasons. Repair people are therefore sometimes called upon to wire a multiconductor connector in the field, often within the narrow confines of a repair van or telephone equipment closet where support systems such as AC power and/or compressed air lines are not likely to be available. The use of semiautomatic termination equipment in such applications is not feasible due not only to space and support system limitations, but due as well to the economic impracticablity of equipping repair personnel with large, expensive termination machines.
Thus, there exists a specific need for an inexpensive, portable and compact termination apparatus suitable for use by repair people who are occasionally called upon to wire a multicontact connector in the field. While semiautomatic termination machines are not well-suited to meet these needs, manually operated termination devices heretofore available in the marketplace or suggested in the prior art have also been, for the most part, unduly expensive, bulky, and oftentimes too complicated for efficient reliable operation by the occasional unskilled user. In addition, these devices typically require considerable room for operation, room which might not be conveniently available in field wiring situations.
Among the design concepts employed in prior manually operated termination devices is that shown in U.S. Pat. No. 3,965,558. The termination machine described therein includes a wire-positioning comb and a retention spring which initially align and hold the insulated wires and a clamp which holds the wires in position as the wires are trimmed to length. Once trimming is completed, the spring and comb are moved away from the wires, and the connector is simultaneously moved into position with the row of contacts on one side of the connector in alignment with the clamped wires. A ram unit accompanies the connector as it is moved into this position so that the ram blades can be driven against the entire group of wires to terminate them in their respective contacts. A manually operated cam and lever mechanism provides the driving force to the ram blades. It is noteworthy that this machine requires full-sized spring, comb, clamp and ram components to effect wiring of one entire side of the connector. This, of course, results in a correspondingly large machine which requires two separate operations to wire both sides of the connector. Furthermore, in order to produce the termination force required to properly and uniformly seat all of the wires on one side of the connector in their respective contacts, a cam and lever mechanism having a relatively long handle which operates in a broad arc is provided. This mechanism requires considerable operating clearance, rendering the machine ill-suited to operation in confined areas.
A somewhat different approach to manual termination of conductors to a multicontact connector is illustrated in U.S. Pat. No. 4,048,711. There, the apparatus includes a fixed connector holder with guide combs positioned along either side of the connector, each guide comb being full-sized to accomodate all of the conductors to be terminated to the contacts along the corresponding side of the connector. Ram blocks carrying a like number of rams are carried by ram arms having force amplification arms. Operation of the apparatus proceeds by laterally moving the guide combs out of the way of the connector holder, mounting the connector in place and returning the combs to their loading position whereupon the conductors are dressed into the comb interstices. The ram arms are then pivoted to a closed position to laterally force the conductors into their corresponding contacts. Relatively complex alignment and fulcrum structures are provided to properly align the rams with the contacts and to insure parallel movement of the rams at the termination end of their arc of movement. Also, as in the case of the previously mentioned apparatus, this apparatus utilizes full-sized combs and ram blocks, both corresponding in size and capacity to the number of contacts mounted in the connector, as well as force amplification arms operating in a broad arc and requiring considerable clearance. Such an arrangement again results in a bulky tool requiring the careful application of considerable termination force to insure that the numerous conductors being handled at one time are properly seated in their respective contacts.
Thus, the need for an inexpensive, portable and compact termination apparatus suitable for use in wiring multicontact connectors in the field has not been satisfied by prior art termination tools, and the need for a relatively inexpensive conductor termination apparatus suitable for operation in the field remains.